The operational efficiency and the overall power output of a gas turbine engine generally increases as the temperature of the hot combustion gas stream increases. High combustion gas stream temperatures, however, may produce higher levels of nitrogen oxides (NOx) and other types of regulated emissions. Such emissions may be subject to both federal and state regulations in the United States and also may be subject to similar regulations abroad. A balancing act thus exists between the benefits of operating the gas turbine engine in an efficient high temperature range while also ensuring that the output of nitrogen oxides and other types of regulated emissions remain well below mandated levels. Moreover, varying load levels, varying ambient conditions, and many other types of operational parameters also may have a significant impact on overall gas turbine efficiency and emissions.
Lower emission levels of nitrogen oxides and the like may be promoted by providing for good mixing of the fuel stream and the air stream prior to combustion. Several types of known gas turbine engine designs such as those used in Dry Low NOx (“DLN”) combustors generally premix the fuel stream and the air stream upstream of a reaction or a combustion zone so as to reduce NOx emissions via a number of premixing fuel nozzles. Such premixing tends to reduce overall combustion temperatures and, hence, NOx emissions and the like.
The interface between internal components of a DLN combustor, however, may vary from typical baseline designs. For example, if the baseline design is used in a DLN combustor, the anti-withdraw tabs from a combustor cap may expand significantly in an axial direction and stick out of the cap into the open space. These tabs thus may be prone to damage during handling and assembly. Other design distinctions also may be present.
There is thus a desire for an improved DLN combustor and the like. Such an DLN combustor may provide an improved liner retaining feature for simplified manufacturing and design while maintaining overall efficient operations with low emissions.